IndiaBIX

Electronics and Communication Engineering - Exam Questions Papers

Exercise : Exam Questions Papers - Exam Paper 11
41.
The switching expression corresponding to :
f(A, B, C, D)= ∑(0, 3, 4, 7, 8) + (10, 11, 12, 14, 15) is:
C D + B C
C ⊙ D
C ⊕ D
CD
Answer: Option
Explanation:

42.
For each of the positive edge-triggered J-K flip flop used in the following figure, the propagation delay is ΔT

Which of the following waveforms correctly represents the output at Q1?
Answer: Option
Explanation:

Two JK flip flop. Thus propagation delay will be 2ΔT

Frequency is getting reduced by a factor e.

43.
Given the function F(A, B, C, D) = m(0, 1, 2, 3, 4, 6, 8, 9, 10, 11, 12). The minimized form of the function can be given by :
A + D B + C B
(B + C)(A + B + C)
(B + D)(A + B + C)
C B + A D + B
Answer: Option
Explanation:

Given S(A, B, C, D) = m(0, 1, 2, 3, 4, 6, 8, 9, 10, 11, 12)

S = (B + D)(A + B + C) .

44.
For the network shown, determine z1 , z0 and Av
zi = 1.067 Ω; z0 = 3 kΩ; Av = 280
zi = 1.067 Ω; z0 = 3 kΩ; Av = - 280.37
zi = 937 Ω; z0 = 3 Ω; Av = 281
zi = 937 Ω; z0 = 33 kΩ; Av = - 280.37
Answer: Option
Explanation:

= 24.04 μA

IE = (1 + β)IB = 2.428 mA;

= 10.7 Ω

(i) zi = RB||Bre =

= 0.937 K = 1.067 K

(ii) Z0 = RC = 3 kΩ

(iii) = -280.37

∴ Zi = 1.067 KΩ;

Z0 = 3 KΩ;

Av = -280.37 .

45.
A germanium diode has a reverse saturation current of 30 μA at 125°C and forward current of 1 mA at a forward potential of 0.8 V and the reverse potential is 0.6 V What are its dynamic forward and reverse resistance at this temperature.
10.7 Ω, 70 kΩ
34 Ω, 20 kΩ
80 Ω, 20 kΩ
800 Ω, 40 kΩ
Answer: Option
Explanation:

We have,

I = I0•(eV/nVT -1)

∴

For forward voltage greater than few teeth's of volts, I >> I0

∴

∴ Forward dynamic resistance,

= 34.3 Ω

Reverse dynamic resistance = = 20 kΩ.

Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers